Core E: Imaging Project Summary Structural MR and amyloid PET imaging have been proposed by the National Institute on Aging as methods to subdivide preclinical Alzheimer Disease (AD) into discrete stages of (1) amyloidosis, followed by (2) amyloidosis plus neurodegeneration, both of which precede (3) subtle cognitive decline, followed by the clinical progression to mild cognitive impairment (MCI) and AD dementia. The HASD Imaging Core will provide MR and PET support to the HASD Projects to test how these proposed stages relate to the transition for normal to impaired cognitive performance (Project 1), sleep disturbance (Project 2), and genetic analyses (Project 3). The following Specific Aims will be pursued: I. Combined PET-MR scanning for brain structure, function, and amyloid pathology. For the entire combined HASD and ADRC cohorts, we will perform brain MRI and florbetapir F18 (AV45) amyloid imaging every three years (200 participants/year). II. Provide data processing for these imaging tests, to include (2a) matched regional volumes, thicknesses, and quantitative PET analyses, (2b) quantitative individual longitudinal participant reports compared normative values generated by the cohort, and (2c) grouped regional reports based on classifications derived from the Projects and Cores. III. Generate an online accessible resource containing source imaging (DICOM), processed imaging, and clinical and biomarker characterization to facilitate data sharing outside of our institution, including contributions to the private-public partnership developed by JC Morris, HASD PI, and T. Benzinger, HASD Imaging Core Leader, with Avid/Lilly. This partnership allows funding for longitudinal MR and amyloid PET imaging for the entire cohort.